I am new to VB and Visual Studio and my question is maybe stupid.
I would like to make a click event for each element inside a form to do the same thing (e.g me.close()).
Is there a way to include all the elements of the form in a single event call or should I have to make a click event for every element that has the same code inside?
If your event is too big then you can write a public/private sub() and then call it from elsewhere. But if your code is only like a small event e.g. me.close() then writing at two or three places doesn't make the program too long, but if you have controls in hundreds then you can write an event like
E.g. for each control in panel/canvas etc (specify collection) and call
Me.close
Related
I am creating an application which requires dynamically loaded controls (to be precise buttons). These buttons are exactly the same, therefore the problem is not creating controls programatically, but making them work somehow. Each button should open a form, the form is being based on some data from the button. I'd like to have all the buttons use one event handler and open forms accordingly to the data it contains. Is there any way to do so? I don't know the types of these forms yet, therefore I can't use pre-defined "select case" or anything that would limit possibilities.
Another problem is that I would like to have some of the forms (modules) being "installed" independently. Is there any way to make that possible? I believe that could be completed using dlls, but I'm not sure. Is there any information on that, I've been looking for that for a while, but found nothing.
Regarding your first problem: You can create buttons in code; the answers to the following question should be enough to get you started (it's C#, but the principle is the same):
How to add Buttons in WinForm in Runtime?
In a nutshell:
Read your button configuration data from the database (or configuration file or whatever),
add the buttons to your user interface (see above),
use AddHandler to add an event handler to each of the buttons. For example:
AddHandler myButton.Click, Sub(sender, e)
' Do something
End Sub
(Regarding your second question: 1. It is unclear to me what you are asking and 2. you shouldn't ask two questions in the same SO question. I suggest that you open a new SO question for that and try to explain your requirement more clearly.)
Maybe i have not understand well your answer... But for your buttons:
1) Create a custom control, inheriting the Button control, and add the properties used for the creation of your forms.
2) In the Sub referenced by your eventHandler, the first argument is the control (the button) who raises the event, so you can use it's own properties to create your forms...
Adding to Heinzi's post:
Keep a list of the button names you created for use with AddHandler().
This code isn't exactly on point but it shows how the AddHandler() can be used at runtime:
' hook TextChanged/CheckedChanged for dirty logic
Dim chk As CheckBox
Dim rdo As RadioButton
For Each c As Control In FormDataControls
If c.Name.StartsWith("chk") Then
chk = c
AddHandler chk.CheckedChanged, AddressOf SetDirty
ElseIf c.Name.StartsWith("rdo") Then
rdo = c
AddHandler rdo.CheckedChanged, AddressOf SetDirty
Else
AddHandler c.TextChanged, AddressOf SetDirty
End If
Next
FormDataControls is my list of controls to target. In my case I use the Tag property to designate data controls.
I don't know how to put it right, but I have a vb.net winform app in which I want to use a customcontrol so I can re-use the logic on multiple forms. I know how to set values in this control from the parent (using properties in the control). But now I want to call a specifiek function on the parent form. Im my case LoadData() which is a procedure of the parentform. How can I do this?
I know I can reference the parent form by using Me.ParentForm in the usercontrol. But I cannot call the LoadData() procedure in the parentform.
Any help? This is a winforms app, not a ASP.NET app.
T.I.A.
[Edit]
I could solve my problem using this example found right here. This is working fine
First, a UserControl is for reusing GUI logic, so I hope that is what you meant. If you are trying to reuse non-GUI logic you might want to create some stand-alone classes for that.
Second, it is generally bad design to call back up to the parent form in the way you describe because it makes the UserControl less reusable and it creates an overly tight binding between the two. You should, if at all possible, push the data down into the UserControl instead.
If you can find no way for the Form to push the data down (perhaps because it is based upon a UI interaction within the UserControl), you have a couple of other options. The first is to wrap up the data-loading behavior into an object that can be passed to the UserControl during initialization, and the the UserControl can access the LoadData method on it as needed. Another approach is to have the UserControl define a set of Events that can be used to request external data from the form. I like to use the "Query" prefix on these kinds of events. So when a fetch button is tapped on your UserControl, it raises the "QueryData" event, and the form that is handling that event responds by populating a data container of some sort that is part of the custom EventArgs.
Either of these can be expanded upon if you need more assistance.
Upon re-reading the question, I it looks like perhaps my approach is over kill. I was under the impression that the LoadData was a method in the Form that loaded data into the UserControl. If it is just a simple call then focus on the event portion of my answer and ignore the data container portion.
I would add an event to your control and handle it on the form the control is part of.
In your control, put something like this:
Public Event LoadData(ByVal sender As Object, ByVal e As System.EventArgs)
And in your form, you can have something like this:
Private Sub UserControl1_LoadData(sender As Object, e As EventArgs) Handles UserControl1.LoadData
'...Your code here
End Sub
I'm working in a windows application. using VB.NET 1.1
I have an empty form, and I want to generate my design in load session (not in form_load event! but in my form's constructor)
So I know I must generate my components in constructor, but I don't know how to generate button events. I mean I haven't any button in design mode, and these are generating in run-time mode. so how I set button events in this session?
And if you have a better solution for run-time design generation, give it to me. thanks ;)
A few things.
You may add controls at practically any point. It can be in the constructor, the Load, in response to another event, or when a custom method is called.
You can wire up events by using AddHandler myButton.Click, AddressOf Button_Click. You'll have to define the Button_Click event handlder and it will need to have the appropriate signature, which for a button click is (sender as object, e as EventArgs).
When in doubt, temporarily add a real control to you form and go to the hidden designer code (MyForm.vDesigner.vb) and see what is generated as a sample. Copy that code and move it into the main populating code. Then delete the control.
Good luck!
I just want to connect two arbitrary controls, so that if one is clicked, the other should act as though it's clicked - is this even remotely possible? it seems like it SHOULD be so easy, but the internet seems dry, unless I just don't know how to ask the question properly... I see a way to "click" a button control, but what if the target is not a button? - I don't know the name of any function that might be triggered by this control's click event, so I can't call it directly. I would guess there is some way of using Windows APIs, but I can't find anything that's nice, simple VB
Example
I click a Label control on the form. I want to handle that click event, run one line of code, then simulate a click event on an associated RadioButton control
Is this possible? How?
If you must, call (System.Windows.Forms.Controls.)Control.InvokeOnClick
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.invokeonclick%28v=vs.71%29.aspx
or even RadioButton.PerformClick
http://msdn.microsoft.com/en-us/library/system.windows.forms.radiobutton.performclick.aspx
A better way would be to create a common Subroutine that would be called on click of either controls. This way clicking on controls will execute their own code which can differ, and some common code as well.
This is how you accomplish executing the same code regardless of which control event was fired.
Private Sub ClickMe()
'code to execute
End Sub
Private Sub label1_Click(...) ...
ClickMe()
End Sub
Private Sub rb_checked(...) ...
ClickMe()
End Sub
All,
I have a TabControl in an application that started behaving strangely. Some background...
This program was converted from VB6 to VB .NET 2008, and used to refer to forms using their class names. In other words, I might have a form class called frmFoo. In the code for the program you might see:
frmFoo.Show()
or
frmFoo.UserDefinedProperty = True
During some recent changes, I created variables to represent instances of my forms much like these:
Public MyForm as frmFoo
MyForm = New frmFoo
MyForm.Show()
In doing so, I also removed code from the form's Load event handler and put it in the form's constructor.
When the form loads, or when a document is loaded and should influence the TabControl's selected index, something like the following will not necessarily fire the SelectedIndexChanged event.
MyForm.tbsForm.SelectedIndex = ValueReadFromFile
...or...
MyForm.tbsForm.Tabs(ValueReadFromFile).Select
Sorry to be so wordy, but there's more. If I open the form and look at the TabControl to verify that it's been set properly, everything works like it's supposed to. The misbehaving TabControl is contained within another TabControl, so I have to click the parent TabControl to see it. If I can see it, and run a test, the test always works. If I can't see it, and run a test, the first test I run will not fire the event. ...paging Dr. Heisenberg...
It's almost as if the control has to be initialized first by changing the value or making it visible onscreen...I'm totally lost on this one. It's the most unusual behavior I've ever seen. And everything worked perfectly before I began using variables to represent forms and placed the Load event code into the form constructors.
Can anyone help, or at least put me out of my misery?
SH
-------------------------------------------------------------- Edit #2
I just performed a test after having attempted to eliminate some of the variability in the behavior. But I wanted to confirm the previously-stated behavior.
I opened the program and read a file. This file contained a value that should have triggered the event handler. Without making the control visible, I can change the SelectedIndex property of the tab control without the event firing.
I closed the program down again, and reopened it. This time, selected the parent tab that allowed the child tab (the one whose event I'm concerned with) to become visible. I then selected a different tab in the parent control, meaning that the child control was no longer visible. When I opened the same file as before, it fired the event.
I'm tempted to implement a flag that confirms that the control has been repainted or whether the parent tab has been displayed. I may have to fire the event in code if the flag isn't set.
I want to reiterate that everything worked when the program referred to the forms by their class names and much of the arrangement of controls on the forms was done in the load event. Now the program creates variables and the arrangement of the controls is done in the form's constructor. I'm sure this has something to do with the problem I'm having, but I can't understand how. Any wisdom to share?
MyForm.tbsForm.SelectedIndexChanged = ValueReadFromFile
doesn't make a lot of sense. Is tha trying to assign a handler to the SelectedIndexChanged event? or is ValueReadFromFile the name of the tab?
What you're saying is that you have two tab controls, say, A and B. Tab control B is contained within a tab of A, and unless A has the tab page selected that contains the tab control B, the SelectedIndexChanged event of B will not fire if you change its tab programatically?
In which different ways have you tried to select a tab within the child tab control, and when is this code being executed?